Tuesday, 8 July 2014

Big, Small, Wide, Tall, You have brains in your head. You have tools you can use, you can design a 3D printer any way you choose :) - thanks for the positive thinking Dr Seuss.

This is a summary post, going over some of the machines I have been working on over the last 6 months. Much more information, design details and files are on the way, just fighting for time at the moment.

Back in Feburary (13th) I posted an update of my adventures, and a picture of me for support of the open-hand project, in the background you can see my machines in their early development stages, not many people spotted them, a few did, you know who you are and get 10,000 bonus points, well done :)

And a brightness warning ! - I always let my kids decide on the colour scheme for all my 3D printer prototypes, so watch out below - some of them are very bright and bold !

Recent Development History -

3DR was my attempt to try and keep Delta printers using 3D printed parts, and take more of a RepRap approach instead of the trend in machining everything for 'professional' results. 3DR seems very popular and I put that down to the majority of parts still being 3D printed, even if they are a little more complicated and time consuming to produce parts than other RepRap machines.

Other than lots of variants and diversification by other people in the community, I have not needed to do anything to the original design of the 3DR, it's still my go-to printer for many objects.

I want to expand on the 3DR family, this post is an overview of the work in progress machines I have going on at the moment and a little more about them.

And before we go any further, I firmly believe we can't have enough RepRap designs, variation and machines, the more the better. None of the following replace 3DR, they all add to the RepRap family.

I had a few things underway and 3DRnano is starting to be a very capably and portable 3D Printer.

The clear/Polycarbonate carriage in the middle is a normal 3DR using LM6UU linear bearings. On the left is a 3DRmega (see below) Using LM10UU bearings and rods and finally on the right is a 3DRnano that uses tiny little LM4UU bearings.

For some idea of scale, left is the nano almost fits inside and actually provides more print area over the physical size than a normal 3DR.

Using the j-head as a light-weight hot-end for now, but a smaller or stainless steel trimmed down e3d V6 would be great ;)

It uses tiny little everything, including LM4UU bearings and 4mm rods ! Spools, carriages and spectra-line, all small and detailed.

Very tiny carriages, even the smallest Ty-wrap looks large with a 4mm Bearing.

Arm assembly is similar to the normal 3DR, just using even smaller parts.

The assembled nano arms do not compromise much on print area or movement, and are just a little scaled down from normal 3DR arms.

It's designed to be Battery and/or Solar powered, light and all the 3D printed part to fit on a 200mm x 200mm bed.

Motor choice -

Top to bottom NEMA17, NEMA14, NEMA11 & NEMA8

The spool for a NEMA8 was so small to print, but actually came out and performed very well.

For the prototype I experimented with NEMA8 motors, you can see one fitted above, for this size printer NEMA8 proved to be just a little weak, but you could make an even smaller printer using one (3DRpico?)

Lots of people said after I posted various images of 3DRnano - put it up on Kickstarter, and yes I could especially as even the most unbelievable things seem to get funded without any issue at all - Anyone for Potato salad? - head in hands, they are not even trying, and it's working...

Now for something rather BIG -

3DRmega -
This one is kind of self explanatory, it's big and most things are scaled-up -

This is a really old picture, apologies for that, where it's being developed at the moment I simply cant get back enough to fit it all in the photo.

Sketchup again for the design, what can I say. It still works well for me and it's so nice to see a model turn into a real thing without errors or problems. I only made one set of files from the design and everything fitted perfectly.

Painful development -

This development has gone really well for the printed and mechanical design, and much less smoothly almost everything else, especially with choices of electronics, power, wiring and the (arrggghhhh - see below for my pain) heated bed.

Success! (prototype, should have just stopped) -

I actually has the prototype up-and-running without a heated bed in Feb2014, my aim then was to work more on cement printing and more exotic extruders (more on that in the next post).

I made the mistake of doing a re-design and adding a heated bed :(, new Smoothie electronics :) and industrial stepper drivers, all great things, but so much more development pain. To give you an idea of the up's and downs on this project, I totally designed, refined and finished Sli3DR (see below) during my sulking phase of V2 3DRmega...

Well it's almost all finished now and worked out, here is more of the progress and some of the setbacks.

Bigger Electronics - The great ARM based Smoothie board is being used for the (new) prototype.

Bigger Rods and Frame (10mm Rods and 30mm Aluminium box-section)

Bigger Printed parts - most parts are 100+mm is size (total printed parts weight is just under 2KG)

Bigger Print head / multiple / materials / feeds etc.

3DRmega now stands around 1.8M tall.

For some time now I have specifically wanted a printer that I could place down onto almost any surface (to print directly onto) - that means not having parts, electronics, motors or even any real structure at the bottom of the machine. The reason for this is so you can print things 'in place' - like a Stone sculpture directly onto a paving slab already fitted - cool !

The nano and mega for scale.

A set of 3DRmega 3D printed frame parts, just under 2Kg of filament used for these, they are also designed to minimize warp and maximise adhesion to the build platform.

The carriages snap-fit onto LM10UU Linear bearings and are running on 10mm smooth stainless steel rods, just like 3DR but bigger and stronger.

Left to Right - LM10UU, LM8UU, LM6UU and LM4UU

Integral belt lock and points to attach the delta arms.

When assembling the delta arms, it's vital to get the flat surfaces of the universal joints parallel and spaced perfectly apart. I used a simple wooden Jig and bolts to make sure everything was lined up before tightening everything and adding super-glue.

The arms are made from carbon fiber tent poles, cut to size and have an all metal universal ball joint fitted to each end. This allows the center carriage to move in any direction as each arm moves up and down.

The center carriage is one of my favorite mega parts, it's solid and not yet quick-fit is easy to install alternative extruders.

The entire frame is made of just three different lengths of 30mm Aluminium box section.

When designing the printed parts I added various viewing windows, in this one you can see the pencil center line on the aluminium section lines up the the point of the RepRap logo, this makes it easy to get everything lined up correctly before doing a final check and tightening.

The frame is solid but to aid with both thermal stability when printing very large parts and for extra light-weight support, 10mm clear corrugated poly-carbonate roofing sheeting is wrapped and fixed around the outer frame, an opening door allows full access inside the build chamber.

Smoothie electronics, power supplies and industrial stepper drivers sit inside the top cover for the V2 design.

Like the nano, but unlike the standard 3DR I have mounted the Motors at the top, this allows much more freedom for the design and flexibility of printing on almost any surface.

Even with everything fitted including side panels 3DRmega can still be lifted, moved and re-positioned by hand with only one person. I have not weighed it, but I'm estimating it's under 18Kg in total.

Extruders -

I designed a few different extruders for the mega, the main requirement was at least one design that didn't use a bowden feed and fed 3mm material, after some interesting re-design around the available 3D space when the arms move around, I ended up with a nice vertical geared design that's stable and works amazingly well.

I have a few other very exciting extruders to share soon, stay tuned for more info :)

Glass -

For the heated bed I had been on the lookout for some round sheets for a while, whilst on a routine shopping trip I spotted a vintage 70s mirror, almost the correct size, I bought it for £2.50 and was rather impressed with it.

Upon closer inspection it had a date on the back of the mirror, 1977, it's almost the same age as me! I decided not to use it as the glass and mirror looked quite brittle.

For ease of use, simple fitting and a solid base. I ended up with a 12mm Ply base, Cork insulation, thermally reflective sheets (see below) heated bed and a 4mm sheet of glass on top.

These grill and oven pads are amazing, they have a highly reflective metal surface, and thermal insulation on the back - I use them on all my heated bed's - One fits a normal Prusa heat-bed, tape more together with PET or Kapton for bigger requirements. Very easy to cut to size too.

and a cork base is not required for a normal heat-bed, but I added one underneath the fat pads to be sure no heat would be wasted.

Disaster strikes -

I spent quite a while on the heated bed design for 3DRmega. It's a big sheet of glass to heat and insulate well.

Shortly (like 5 mins) after completing the one-of-a-kind and very large 36V heated bed prototype, with glass top and triple insulated base. I went and dropped a heavy NEMA23 motor right onto one corner causing this wonderful mess.

I had just tested it, worked perfectly... then butterfingers, smash :(

If it had only been the glass that got damaged I would not have been so annoyed with myself, but a NEMA23 is heavy and the heated bed and wiring needed repair. Also sourcing more (toughened - this time) glass ended up taking a lot longer than I expected.

And guess what? When I posted about 3DRmega in February, I had a flood of requests for design files (I posted way too early, sorry) and also hundreds of people saying I should put it up on Kickstarter...

That's enough of the mega for now, I'll post more and release the design files when I'm in a better mood with it :) and I can document them a little better. I will also get some video's done to show it printing, it's even more impressive than when you saw your first delta printer, big smiles for big 3D printers.

3DRultra -
Well, not yet. but for a really massive Delta printer, moving to LM16UU / LM20UU or linear Rails would start to give you a very large printable area indeed - Bigger frames can be made out of even larger Aluminium box sections, even scaffolding poles if you want. If someone wants to fund the parts, I'll design and make it... (seriously, get in touch).

This post is getting rather long, so I'll delay the full post about Sli3DR for a few days, here is a little of what it's all about and as so many people asked me about the mechanism, that's shown below too -

Sli3DR - (pronounced Slider)Sli3DR is not a Delta based printer, rather it's based on an intriguing 'unnamed mechanism' that was floating around on the RepRap Forum and G+ last year. Billy ZelsnackIdentified it as used in a very old (Rikadenki) Pen Plotter design here. A few people have tried it out for 3D printing using off the shelf mechanical parts, I wanted to make it with 3D printed parts and Spectra Line based on this mechanism.

Maybe it was fate but it was also only a few weeks after the Ultimaker 2 was announced, and not yet actually ever managing to be an Ultimaker owner (one day) - I always wanted to build something similar.

After using the Tantillus (very similar to Ultimaker position mechanism) and looking into both CoreXY and HBot systems for a while this 'unnamed mechanism' seemed perfect. It's very old, not patented, (or if it ever was that's expired), and I can use the same Spectra line as the Tantillus and 3DR's - Now to design it.

It's using Spectra Line on all the axis drives, including the Z axis - my quest for ideal Z movements moves ever closer to perfection.

Tim Rastall was also designing a Super-big Tantillus called the Ingentis around the same time. I printed an early set of Ingentis parts, but after seeing the above mechanism I just had to design a printer based on it. I did borrow the style of Tim's Z-Axis arms, (Thanks Tim) everything else needed to be designed and had to be able to be scaled up or down.

I used Sketchup again, I still find it east to use but I must admit after getting in all the 2D dimensions and measurements, moving to 3D parts does not give you much chance to refine the concept into a beautiful looking 'product' before you get trapped into blocky looking parts. But it did the job for a new concept design. - I desire a much more Organic feel for the the next project.

If you were wondering, the parts are printed in Faberdashery Cyber Yellow, it's ultra day-glow Yellow and looks great, day or night.

Hot end and carriage system

That's not all Kapton tape - It has some layers of ceramic insulation.

If you want to spontaneously fund me 'without a Kickstarter' I have a donate button over on the left of my blog.

Potato salad is over $35K and rising as I type this - madness, total madness. - That said I do make a wicked Chili...

RepRap Barcelona - mash.

And talking of Potatoes, RepRap Barcelona have done a mash potato extruder based on my Universal paste extruder design - great work guys :)

Other news / updates -

The UK 3D Printing TCT Show is happening in 30th Sept - 2nd October, over three days this time, the RepRap hub is planned to be bigger and better than ever, but only if people get involved and want to help make it a success - if you want to take part please e-mail me on - tctshow@reprapmagazine.com

Many companies have decided to take their own spaces so if you want to be part of the RepRap Community Hub, then do let me know.

3D Printing development and the 3D Printing industry is a massive roller-coaster, I would have to say that at the moment I'm on a big downward plunge into a dim tunnel, my wallet has fallen out and people are screaming all around me. See you next time.

About Me

Richard Horne (RichRap)
is an Electronics Engineer, Product Designer, Salesman, and Problem Solver
working in a wide range of industries and applications, across many platforms
and technologies for the last 20 years.